The effects of oxygen inhalation, nitroglycerin (NTG) and prostaglandin E1 (PGE1) on pulmonary hemodynamics and blood gases were studied in 15 patients with chronic lung disease (CLD). Cardiac catheterization was performed with Swan-Ganz catheter, and pulmonary hemodynamics and cardiac output were measured. After baseline hemodynamics and blood gas measurements were made, 15 patients inhaled oxygen for 15 minutes and the same measurements were repeated. Twenty minutes later, oxygen inhalation was stopped. Then the 15 patients were divided into two groups; one group was administered sublingual NTG (7 patients) and the other was administered PGE1 by continuous intravenous infusion (8 patients). Pulmonary hemodynamics and blood gas measurements were then performed. Oxygen inhalation significantly reduced mean pulmonary artery pressure (from 22.2 +/- 8.8 to 20.0 +/- 6.4 mmHg; p < 0.01) and heart rate (from 78.1 +/- 12.0 to 75.5 +/- 12.5 beats/min; p < 0.05). With respect to oxygenation, oxygen inhalation significantly increased PaO2 (from 68.6 +/- 10.7 to 113.4 +/- 31.4 mmHg; p < 0.01), PvO2 (from 35.1 +/- 3.7 to 38.0 +/- 3.3 mmHg; p < 0.01). Therefore, oxygen inhalation was thought to be useful in patients with chronic lung disease with pulmonary hypertension. Sublingual administration of NTG significantly reduced mean pulmonary artery pressure (from 24.1 +/- 0.2 to 17.6 +/- 6.8 mmHg; p < 0.01), C.I. (from 2.9 +/- 0.2 to 2.3 +/- 0.2 ml/min/m; p < 0.01), O2-transport (from 589.1 +/- 168.4 to 457.0 +/- 105.8 ml/min; p < 0.01), and had a tendency to decrease PvO2 (from 34.3 +/- 3.0 to 32.1 +/- 1.8 mmHg; p < 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)